Delivered by Ingenta to: McMaster University IP: 5.101.222.177 On: Sun, 19 Jun 2016 02:43:01 Copyright: American Scientific Publishers Copyright © 2014 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 14, 9143–9147, 2014 www.aspbs.com/jnn Aerosol Approach for Hollow Spheres of a Porous 3D Carbon Nanotube/CuO Network and Their Anodic Properties for Lithium-Ion Battery YunKyoung Kim 1 , SeungIl Cha 2 , JunHo Lee 1 , and SoonHyung Hong 1 ∗ 1 Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Republic of Korea 2 Advanced Materials and Application Research Division, Korea Electrotechnology Research Institute, Changwon, 641-120, Republic of Korea Hollow spheres consisting of porous CNT/CuO nanocomposite networks were prepared by aerosol process and their enhanced anodic properties for lithium-ion battery were investigated. Hollow spheres of CNT/CuO nanocomposites showed a 3D network wherein the length of the electron path was quite short compared with the agglomerated CNT/CuO nanocomposites. From electro- chemical measurements, CuO itself shows poor discharge capacity and cycling performance due to its low electronic conductivity. In the CNT/CuO nanocomposite, enhanced discharge capacity was observed and showed similar values regardless of the morphology. With the addition of CNTs to CuO, CNTs can form a network that acts as an electron path-way in the insulating CuO matrix, lead- ing to increased electrical conductivity. The morphology of nanocomposite affected cycle stability. Hollow spheres of CNT/CuO nanocomposite showed better cycle stability than that of agglomer- ated CNT/CuO nanocomposite. The hollow sphere of a CNT/CuO nanocomposite comprising a 3D network of CNTs can be applied as a high capacity anode material in Li-ion batteries. Keywords: Carbon Nanotubes, Nanocomposite, Lithium-Ion Battery. 1. INTRODUCTION Lithium-ion batteries have become the dominant power sources for portable electronic devices. 1 These batteries are also expected to be widely used for the power supply in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Due to demand for higher energy storage for new applications, huge efforts have been made to develop new electrode materials for lithium-ion batteries with improved electrochemical properties. Recently, transition metal oxides have been studied as anode materials of lithium-ion batteries. The use of transi- tion metal oxides as electrode materials for next generation rechargeable lithium-ion batteries with both high energy and high power densities have been widely studied owing to their high theoretical capacity, high safety, environ- mental benignity, low cost, etc. 2 Transition metal oxides operate by a mechanism based on a process termed the conversion reaction. The reaction leads to the formation ∗ Author to whom correspondence should be addressed. of nanosized metal particles and amorphous Li 2 O, via a reversible process, and the associated lithium storage capacity can be maintained for hundreds of cycles. Among these transition metal oxides, CuO could be an attractive anode material because it is inexpensive, non-toxic, easily produced, readily stored and has a high theoretic capacity (670 mA h g -1 ). However, the conversion reactions suf- fer from poor kinetics, leading to low cycle performance. One of the challenging issues related to their use for high performance lithium-ion batteries is tackling their poor electronic conductivities. Research has focused on enhanc- ing electronic conduction by using carbon-coatings 3 4 or other electronically conductive additives. 5 6 Carbon nano- tubes (CNTs) are attractive materials for energy stor- age applications such as supercapacitors, fuel cells, and lithium-ion batteries due to their high chemical stabil- ity, high aspect ratio, and excellent mechanical, electri- cal, and thermal properties. 7 In particular, it has been reported that the specific capacity of Li-ion battery can be improved by the superior electric conductivity of J. Nanosci. Nanotechnol. 2014, Vol. 14, No. 12 1533-4880/2014/14/9143/005 doi:10.1166/jnn.2014.10089 9143